U.S. patent number 5,597,859 [Application Number 08/446,119] was granted by the patent office on 1997-01-28 for seed process for salt dispersion polymer.
This patent grant is currently assigned to Nalco Chemical Company. Invention is credited to John R. Hurlock, Manian Ramesh.
United States Patent |
5,597,859 |
Hurlock , et al. |
January 28, 1997 |
Seed process for salt dispersion polymer
Abstract
A novel dispersant system is disclosed for use in forming
dialkylaminoalkyl (meth)acylamide polymer dispersions.
Inventors: |
Hurlock; John R. (Hickory
Hills, IL), Ramesh; Manian (Naperville, IL) |
Assignee: |
Nalco Chemical Company
(Naperville, IL)
|
Family
ID: |
22591528 |
Appl.
No.: |
08/446,119 |
Filed: |
May 19, 1995 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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163778 |
Dec 9, 1993 |
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Current U.S.
Class: |
524/458; 526/307;
525/217; 524/521; 525/218; 526/307.7; 526/310; 524/555; 526/307.3;
526/307.2 |
Current CPC
Class: |
C08F
220/60 (20130101); C08F 2/20 (20130101) |
Current International
Class: |
C08F
2/20 (20060101); C08F 2/12 (20060101); C08F
220/60 (20060101); C08F 220/00 (20060101); C08F
002/16 (); C08F 002/28 (); C08F 220/60 (); C08F
220/54 () |
Field of
Search: |
;524/458,555,521
;525/217,218 ;526/307,307.2,307.3,307.7,310 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Michl; Paul R.
Assistant Examiner: Merriam; Andrew E. C.
Attorney, Agent or Firm: Miller; Robert A. Drake; James J.
Charlier; Patricia A.
Parent Case Text
This application is a division of application Ser. No. 08/163,778,
filed Dec. 9, 1993, pending.
Claims
We claim:
1. A process for preparing a water soluble polymer dispersion which
comprises polymerizing a water soluble mixture which comprises:
a cationic monomer represented by the following general formula
(I): ##STR7## wherein R.sub.1 is either hydrogen or CH.sub.3 ;
R.sub.2 and R.sub.3 are each an alkyl group having 1 to 3 carbon
atoms: A.sub.1 is either an oxygen atom or NH; B.sub.1 is either an
alkylene group having 2 to 4 carbon atoms or a hydroxypropylene
group, and X.sub.1.sup.- is an anionic counterion, and/or a second
cationic monomer represented by the following general formula (II):
##STR8## where R.sub.4 is either hydrogen or CH.sub.3 ; R.sub.5 and
R.sub.6 are each an alkyl group having 1 to 2 carbon atoms; R.sub.7
is a hydrogen atom or an alkyl group having 1 to 2 carbon atoms;
A.sub.2 is either an oxygen atom or NH; B.sub.2 is either an
alkylene group having 2 to 4 carbon atoms or a hydroxypropylene
group and X.sub.2.sup.- is an anionic counterion; and,
b. (meth)acrylamide in an aqueous solution of a polyvalent anionic
salt,
wherein said polymerization is carried out in the presence of a
first dispersant polymer which comprises a copolymer of
diallyldimethyl-ammonium chloride and a hydrophobic monomer
selected from the group consisting of dialkylaminoalkylacrylates
having C.sub.6 to C.sub.20 quaternaries,
dialkylaminoalkylmethacrylates having C.sub.6 to C.sub.20
quaternaries, and alkyl esters of acrylic acid, and a second
dispersant polymer which is a water soluble cationic copolymer
composed of at least 20 mole percent of cationic monomer units
represented by formula (II) above.
2. The process according to claim 1 wherein said
dialkylaminoalkylacrylates having C.sub.6 to C.sub.20 quaternaries
are either dimethylaminoethylacrylate benzyl chloride quaternary or
dimethylaminoethylacrylate cetyl chloride quaternary.
3. The process according to claim 1 wherein said
dimethylaminoethylmethacrylates having C.sub.6 to C.sub.20
quaternaries are either dimethylaminoethylmethacrylate benzyl
chloride quaternary or dimethylaminoethylmethacrylate cetyl
chloride quaternary.
4. The process according to claim 1 wherein said alkyl ester of
acrylic acid is ethyl hexyl acrylate.
5. The process according to claim 1 wherein said
diallyldimethylammonium chloride and said hydrophobic monomer are
present in a molar ratio in the range from 99:1 to 20:80.
6. The process according to claim 1 wherein said (meth)acrylamide
is present in an amount in the range between about 20 to about 95
mole %.
7. The process according to claim 1 wherein said cationic monomer
represented by the general formula (I) is present in an amount
between about 5 to about 50 mole %.
8. The process according to claim 1 wherein said cationic monomer
represented by the general formula (II) is present in an amount
between about 5 to about 50 mole %.
9. The process according to claim 1 wherein said dispersant
polymers are present in a combined amount of between about 2.5 to
about 6 weight %, based on the total weight of the monomers of said
dispersion.
10. The process according to claim 1 wherein monomers represented
by the general formula (I) are selected from the group consisting
of: quaternary monomers obtained by treating dimethylaminoethyl
(meth)acrylate, diethylaminoethyl (meth)acrylate,
dimethylaminopropyl (meth)acrylamide and dimethylhydroxypropyl
(meth)acrylate, diethylaminopropyl (meth)acrylamide and
dimethylaminohydroxylpropyl (meth)acrylate with benzyl
chloride.
11. The process according to claim 1 wherein monomers represented
by the general formula (II) are selected from the group consisting
of: methyl and ethyl quaternary of dimethylaminoethyl
(meth)acrylate, diethylaminoethyl (meth)acrylate,
dimethylaminopropyl (meth)acrylamide, diethylaminopropyl
(meth)acrylamide and dimethylhydroxypropyl (meth)acrylate.
12. The process according to claim 1 wherein the process viscosity
during polymerization is about 5,000 cp or lower.
13. The process of claim 1 wherein the process the polymerization
is carried out in the presence of from about 1.5 to about 15% by
weight of a seed polymer.
14. The process of claim 1 wherein the process the polymerization
is carried out in the presence of from about 3 to about 8% by
weight of a seed polymer.
Description
FIELD OF THE INVENTION
The present invention relates to the novel process for the
production of a dispersion of a water soluble polymer.
BACKGROUND OF THE INVENTION
Conventional processes for the preparation of a water soluble
cationic polymer useful as a flocculent include polymerization in
an aqueous solution, water-in-oil emulsion polymerization, and
suspension polymerization in a hydrophobic solvent. Others have
prepared a water soluble, anionic polymer by precipitation
polymerization in an aqueous solution of ammonium sulfate. Still
others have carried out the polymerization in an aqueous solution
in the presence of a polyhydric alcohol or a polyelectrolyte as a
dispersant.
U.S. Pat. No. 4,929,655 (Takeda et at.), which issued on May 29,
1990, and which is incorporated herein by reference, provided a
novel process for preparing a water soluble polymer dispersion
which overcomes the many disadvantages of the stationary
polymerization, water-in-oil type emulsion polymerization and
suspension polymerization processes. This process for the
production of a water soluble dispersion includes the
polymerization of water soluble monomers of 5 to 100 mole % of a
cationic monomer represented by the following formula (I), 0 to 50
mole % of another cationic monomer represented by the following
formula (II) and 0 to 95 mole % (meth)acrylamide in the presence of
1 to 10% by weight of an organic high molecular multivalent cation
comprising a water soluble polymer containing at least a monomer of
formula (II) (i.e., a hydrophilic monomer), based on the total
weight of the monomers, in an aqueous multivalent anionic salt
solution having a concentration of 15% by weight or more. The first
cationic monomer discussed above can be represented by the
following general formula (I): ##STR1## where R.sub.1 is either
hydrogen or CH.sub.3 ; R.sub.2 and R.sub.3 ar each an alkyl group
having 1 to 3 carbon atoms; A.sub.1 is either an oxygen atom or NH;
B.sub.1 is either an alkylene group having 2 to 4 carbon atoms or a
hydroxypropylene group, and X.sub.1.sup.- is an anionic counterion,
and/or a second cationic monomer represented by the following
general formula (II): ##STR2## where R.sub.4 is either hydrogen or
CH.sub.3 ; R.sub.5 and R.sub.6 are each an alkyl group having 1 to
2 carbon atoms; R.sub.7 is a hydrogen atom or an alkyl group having
1 to 2 carbon atoms; A.sub.2 is either an oxygen atom or NH;
B.sub.2 is either an alkylene group having 2 to 4 carbon atoms or a
hydroxypropylene group and X.sub.2- is an anionic counterion.
U.S. Pat. No. 5,006,590 (Takeda et at.), which issued on Apr. 9,
1991, and which is incorporated herein by reference, is similar to
Takeda '655, except that polymerization is carried out in the
presence of both: (1) a water soluble cationic polymer which is
insoluble in an aqueous solution of a polyvalent anionic salt (seed
polymer); and (2) a water soluble cationic polymer which is soluble
in an aqueous solution of a polyvalent anionic salt (dispersant
polymer). The water soluble cationic polymer that is insoluble in
the aqueous solution of polyvalent anionic salt contains at least 5
mole % of cationic monomer units represented by the aforementioned
general formula (I) above and the water soluble cationic polymer
that is soluble in the aqueous solution of a polyvalent anionic
salt contains at least 20 mole % of cationic monomer units
represent by the general formula (II) above.
Although the final polymer dispersion viscosities were
satisfactory, i.e., 1,000 cp or below, the processes disclosed in
U.S. Pat. Nos. 4,929,655 and 5,006,590 proceed through very high
process viscosities (i.e., >100,000 cp and usually as high as
2,000,000 cp), which require the use of a custom built high
viscosity polymerization reactor. Due to these high process
viscosities, the methods disclosed in U.S. Pat. Nos. 4,929,655 and
5,006,590 can only be used in the synthesis of polymer systems
containing low polymer contents (i.e., 15 to 20%).
The present inventors have discovered through extensive
experimentation, that hydrophobically modified
diallyldimethylammonium chloride (DADMAC) polymers can be used in
combination with the dispersant polymers disclosed in U.S. Pat.
Nos. 4,929,655 and 5,006,590 as colloidal stabilizers in the
dispersion polymerization process. The dispersant system of the
invention is highly soluble in water and at least partially soluble
in aqueous salt solutions. The dispersant system has been
demonstrated to facilitate the precipitation process and thereby
very significantly reducing the process viscosity. This allows the
production of high molecular weight polymer dispersions in a
conventional latex-type reactor, thereby avoiding the substantial
costs associated with high viscosity custom built polymerization
reactors. Further, the reduction in process viscosity will allow
the preparation of polymer systems containing higher actives (such
as, from 15 to about 30-40 percent by weight) in latex-type
reactors.
Moreover, it has also been discovered that even lower production
viscosities are maintained through subsequent polymerizations when
from about 1.5 to about 12 percent by weight of polymer from one
polymerization process is used as the seed in the next
polymerization generation of the same polymer. It should be noted
that it has been determined that when the dispersant polymers of
the invention used independently of each other, production
viscosity increases with each successive generation, until, process
viscosity becomes so great that standard latex-type reaction will
not accommodate the process. The present inventors have also
determined that the multivalent anionic salt concentration can be
optimized to control process viscosity.
The present invention provides many additional advantages which
shall become apparent as described below.
SUMMARY OF THE INVENTION
A dispersant system used in forming polymer dispersions which
comprises: a copolymer of diallyldimethylammonium chloride and a
hydrophobic monomer selected from the group consisting of
dialkylaminoalkylacrylates having C.sub.6 to C.sub.20 quaternaries,
dialkylaminoalkylmethacrylates having C.sub.6 to C.sub.20
quaternaries, dialkylaminoalkyl (meth)acrylamides having C.sub.6 to
C.sub.20 quaternaries, and alkyl esters of acrylic acid; and a
water soluble high molecular weight cationic copolymer composed of
20 mole % or more of cationic monomer units represented by the
formula (II), preferably the residual mole % is acrylamide or
methacrylamide.
The novel dispersant system according to the present invention is
particularly useful in preparing a water soluble polymer
dispersion. According to one preferred embodiment of the invention,
the dispersion is prepared by polymerizing a water soluble mixture
of from about 15 to about 40% percent by weight of a cationic
monomer represented by the following general formula (I): ##STR3##
where R.sub.1 is either hydrogen or CH.sub.3 ; R.sub.2 and R.sub.3
are each an alkyl group having 1 to 3 carbon atoms; A.sub.1 is
either an oxygen atom or NH; B.sub.1 is either an alkylene group
having 2 to 4 carbon atoms or a hydroxypropylene group, and
X.sub.1.sup.- is an anionic counterion, and/or a second cationic
monomer represented by the following general formula (II): ##STR4##
where R.sub.4 is either hydrogen or CH.sub.3 ; R.sub.5 and R.sub.6
are each an alkyl group having 1 to 2 carbon atoms; R.sub.7 is a
hydrogen atom or an alkyl group having 1 to 2 carbon atoms; A.sub.2
is either an oxygen atom or NH; B.sub.2 is either an alkylene group
having 2 to 4 carbon atoms or a hydroxypropylene group and
X.sub.2.sup.- is a counterion, and (meth)acrylamide in an aqueous
solution of from 13 to about 18 percent by weight of a polyvalent
anionic salt; wherein the polymerization is carried out in the
presence of the dispersant system of the invention and from about
1.5 to about 12 percent by weight of a seed polymer.
Other and further objects, advantages and features of the present
invention will be understood by reference to the following
specification in conjunction with the annexed drawing.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The dispersant system of the invention includes two polymers which
are used to form polymer dispersions. A first dispersant polymer of
the dispersant system is a copolymer of diallyldimethylammonium
chloride (DADMAC) and a hydrophobic monomer selected from the group
consisting of: quaternized dialkylaminoalkylacrylates (DMAEA),
quaternized dialkylaminoalkylmethacrylates (DMAEM), quaternized
dialkylaminoalkyl (meth)acrylamides, and alkyl esters of acrylic
acid. Processes for synthesizing the first dispersant polymer are
described in detail in co-pending U.S. patent application Ser. No.
08/074,960, filed Jun. 10, 1993, the disclosure of which is
expressly herein incorporated by reference.
A second dispersant polymer is a water soluble high molecular
weight cationic copolymer composed of 20 mole % or more of cationic
monomer units represented by the formula (II) below, preferably the
residual mole % is acrylamide or methacrylamide. An example of the
second dispersant is quaternized polyDMAEA. The second dispersant
polymer is hydrophilic and is discussed in detail in U.S. Pat. Nos.
5,006,590 and 4,929,655 and the discussion of which is expressly
incorporated herein by reference.
The mole ratio of the first dispersant polymer to the second
dispersant polymer in the dispersant system of the invention, is
from about 95 to about 5 to about 5 to 95; and more preferably,
from about 90 to 10 to about 25 to 75.
The DADMAC can be prepared in accordance with any conventional
manner such as the technique described in U.S. Pat. No. 4,151,202
(Hunter et at.), which issued on Apr. 24, 1979, and which is
incorporated herein by reference. The quaternized
dialkylaminoalkylacrylate is preferably selected from the group
consisting of: dialkylaminoalkylacrylates having C.sub.6 to
C.sub.20 chloride quaternary, e.g., dimethylaminoethylacrylate
benzyl chloride quaternary or dimethylaminoethylacrylate cetyl
chloride quaternary. The quaternized dialkylaminoalkylmethacrylate
is preferably selected from the group consisting of:
dialkylaminoalkylmethacrylates having C.sub.6 to C.sub.20 chloride
quaternary, e.g., dimethylaminoethylmethacrylate benzyl chloride
quaternary or dimethylaminoethylmethacrylate cetyl chloride
quaternary. The molar ratio of diallyldimethylammonium chloride to
hydrophobic monomer in the range between about 99:1 to about 20:80,
preferably about 90:10.
According to one embodiment of the invention, semi-batch process is
preferably used to make the DADMAC copolymer dispersants and
comprises the following steps:
a. adding diallyldimethylammonium chloride to a polymerization
reaction vessel in an amount between about 1 to about 19 weight
percent;
b. heating the diallyldimethylammonium chloride to a temperature in
the range between about 47.degree. C. to about 57.degree. C.;
c. adding a polymer initiator dropwise to the
diallyldimethylammonium chloride in an amount between about 0.05 to
about 0.40 weight percent;
d. adding a hydrophobic monomer dropwise to the
diallyldimethylammonium chloride in an amount between about 3 to
about 19 weight percent; and
e. heating the mixture of diallyldimethylammonium chloride, polymer
initiator and hydrophobic monomer to a temperature in the range
between about 47.degree. C. to about 82.degree. C.
Typically, deionized water is added periodically as needed during
the polymerization process in a total amount between about 63 to
about 88 weight percent. In some instances, it is preferable to mix
diallyldimethylammonium chloride with NaCl and deionized water
prior to addition to the reaction vessel. The NaCl is added in an
amount between about 2 to about 3.5 weight percent and the
deionized water is added in an amount between about 1 to about 2.5
weight percent. This diallyldimethylammonium chloride solution has
a concentration of diallyldimethylammonium chloride in the range
between about 50 to about 65.
This semi-batch process produces a hydrophobic dispersant with a pH
in the range from about 3.5 to about 4.5.
The diallyldimethylammonium chloride, polymer initiator and
hydrophobic monomer are heated at a temperature in the range
between about 47.degree. C. to about 57.degree. C. for a period of
between about 6 to 8 hours. Thereafter, the temperature of the
reaction vessel is increased to about 72.degree. C. to about
82.degree. C. for a period of between about 3 to 7 hours. After
polymerization has been completed the copolymer product is
typically diluted with deionized water, cooled and stored.
Alternatively, the hydrophobic monomer can be added in the reactor
along with NaCl, DADMAC and water, and heated to about 47.degree.
to about 57.degree.. The initiator solution is added dropwise,
along with similar DI water addition. The polymer initiator is
selected from the group consisting of
2,2'-azobis(2amidinopropane)hydrochloride (V50), 2,2'-azobis
(N,N'-dimethylene isobutyramidine)dihydrochloride (VA044).
The novel dispersant system according to the present invention is
particularly useful in processes for preparing a water soluble
polymer dispersion. The dispersion is prepared by polymerizing a
water soluble mixture of a cationic monomer represented by the
following general formula (I): ##STR5## where R.sub.1 is either
hydrogen or CH.sub.3 ; R.sub.2 and R.sub.3 are each an alkyl group
having 1 to 3 carbon atoms; A.sub.1 is either an oxygen atom or NH;
B.sub.1 is either an alkylene group having 2 to 4 carbon atoms or a
hydroxypropylene group, and X.sub.1.sup.- is an anionic counterion,
and/or a second cationic monomer represented by the following
general formula (II): ##STR6## where R.sub.4 is either hydrogen or
CH.sub.3 ; R.sub.5 and R.sub.6 are each an alkyl group having 1 to
2 carbon atoms; R.sub.7 is a hydrogen atom or an alkyl group having
1 to 2 carbon atoms; A.sub.2 is either an oxygen atom or NH;
B.sub.2 is either an alkylene group having 2 to 4 carbon atoms or a
hydroxypropylene group and X.sub.2.sup.- is an anionic counterions,
and (meth)acrylamide in an aqueous solution of from about 10 to
about 18 percent by weight of a polyvalent anionic salt; wherein
the polymerization is carried out in the presence of the dispersant
system of the invention and from about 1.5 to about 10 percent by
weight of a seed polymer.
The (meth)acrylamide is typically present in an amount in the range
between about 20 to about 95 mole %, the cationic monomer
represented by the general formula (I) is typically present in an
amount between about 5 to about 50 mole %; and the cationic monomer
represented by the general formula (II) is typically present in an
amount between about 5 to about 50 mole %. The use of the cationic
monomer represented by the general formula (II) is optional. The
dispersant system of the invention is present in an amount between
about 2.5 to about 6 weight %, based on the total weight of the
monomers of the dispersion.
Examples of monomers represented by the general formula (I) include
quaternary monomers obtained by treating dimethylaminoethyl
(meth)acrylate, diethylaminoethyl (meth)acrylate,
dimethylaminopropyl (meth)acrylamide and dimethylhydroxypropyl
(meth)acrylate, diethylaminopropyl (meth)acrylamide and
dimethylaminohydroxylpropyl (meth)acrylate with benzyl chloride.
One preferred monomer is
N-benzyl-N-(meth)acryloxyethyl-N,N-dimethylammonium chloride.
Examples of monomers represented by the general formula (II)
include methyl or ethyl quaternary salts of dimethylaminoethyl
(meth)acrylate, diethylaminoethyl (meth)acrylate,
dimethylaminopropyl (meth)acrylamide, diethylaminopropyl
(meth)acrylamide and dimethylhydroxypropyl (meth)acrylate. One
preferred monomer is N-(meth)acryloyloxyethyl-N,N,N-trimethyl
ammonium chloride.
The inventors have discovered that process viscosities can be
further reduced by carefully controlling the concentration of the
multivalent anionic salt used to deposit the polymer of the present
invention. The multivalent anionic salt in the present invention is
preferably a sulfate or a phosphate, and typical examples of these
salts include ammonium sulfate, sodium sulfate, magnesium sulfate,
aluminum sulfate, ammonium hydrogen phosphate, sodium hydrogen
phosphate and potassium hydrogen phosphate. According to one
preferred embodiment of the invention, the salt is used in the form
an aqueous salt solution at a concentration of from about 16 to
about 18 by weight, more preferably 16.25 to about 17 percent by
weight and most preferably, about 16.5 percent by weight. The
dispersant system of this invention is at least partially soluble
in the aqueous salt solution and highly soluble in water.
According to one embodiment of the invention, a seed polymer is
added before the beginning of the polymerization of the above
monomers for the purpose of obtaining a fine dispersion. It has
been discovered that by adding the seed polymer in a concentration
of from about 1.5 to about 12 percent by weight, process viscosity
can be maintained below 5,000 cp, and preferably below 3,000 cp.
More preferably, the seed polymer is added in a concentration of
from about 3 to about 8 percent by weight, and most preferably in a
concentration of from 5-7 percent by weight. The seed polymer is a
water soluble cationic polymer insoluble in the aqueous solution of
the polyvalent anionic salt. The seed polymer is preferably a
polymer prepared from the above monomer mixture by the process
described herein. Nevertheless, the monomer composition of the seed
polymer need not always be equal to that of the water soluble
cationic polymer formed during polymerization. However, like the
water soluble polymer formed during polymerization, the seed
polymer should contain at least 5 mole percent of cationic monomer
units represented by the general formula (I). According to one
embodiment of the invention, the seed polymer used in one
polymerization reaction is the water soluble polymer prepared in a
previous reaction which used the same monomer mixture.
Utilizing the dispersant system of the invention, and controlling
the concentration of the multivalent anionic salt and the seed
polymer permits the use of conventional latex reactors since the
process viscosity during polymerization is maintained below about
5,000 cp, more preferably below about 3,000 cp. Furthermore,
polymer batch preparations can be made including up to 40 percent
by weight polymer.
The following examples are presented to describe preferred
embodiments and utilities of the invention and are not meant to
limit the invention unless otherwise stated in the claims appended
hereto.
EXAMPLES
The following general procedure was used for manufacturing the
polymer dispersions of the invention. If monomer concentration,
seed concentration, salt concentration or dispersant polymer
concentration was varied, it will be noted below in the individual
example.
A monomer solution was placed into a batch reactor. The monomer
solution includes DR 3000, a commercially available dispersion
polymer available from Hymo Corporation, Japan. The DR 3000
preparation provides 20 grams of the seed polymer in every 100
grams of DR 3000. Also, in every 100 grams of DR 3000, there is one
gram of polyDMAEA.cndot.MCQ dispersant polymer and twenty-two grams
ammonium sulfate, which is the multivalent anionic salt.
Also into the batch reactor was placed the second dispersant
polymer of the invention, a copolymer of DADMAC-DMAEA.cndot.BCQ.
The DADMAC-DMAEA.cndot.BCQ copolymer works with the other
dispersant polymer present in DR3000, polyDMAEA.cndot.MCQ, to
substantially reduce process viscosities.
The monomer mixture used to form a dispersion terpolymer was AcAm,
DMAEA.cndot.BCQ and DMAEA.cndot.MCQ. Co-stabilizers and chelants
were also added when needed. V-50 obtained from Wako Chemical was
used as the polymerization initiator. The multivalent anionic salt
added to the batch reactor was ammonium sulfate. Post reaction
additives generally included ammonium sulfate.
Once all the monomer solution was placed into the batch reactor,
the reactants were heated to 48.degree. C. A nitrogen purge was
used. At 48.degree. C. the polymerization initiator was added. The
reactants were then heated for four hours at 48.degree. C. Process
viscosity was measured throughout the process. The reactants were
cooled and the post addition salt was added.
Example 1
______________________________________ Formula A
______________________________________ DR-3000 20% 300.00 g/60 g
polymer DADMAC-DMAEA.BCQ (20%) 34.75 g AcAm (48.0%) 101.15 g
DMAEA.BCQ (80%) 88.77 DMAEA.MCQ (80%) 25.35 Glycerol 4.20 Versene
0.40 V-50 2.80 Ammonium Sulfate 94.00 DI Water 288.58 Post Addition
Salt 60.00 ______________________________________
Using 6.0 % seed, the dispersant system of the invention, and
17.02% salt, the process viscosity was maintained below 400 cp.
Example 2
______________________________________ Formula B
______________________________________ DR-3000 (20%) 150.00 (30 g
polymer) DADMAC-DMAEA.BCQ (20%) 42.20 AcAm (48.0%) 122.87 DMAEA.BCQ
(80%) 107.78 DMAEA.MCQ (80.5%) 30.78 Glycerol 5.00 Ammonium Sulfate
127.00 Versene 0.30 V-50 3.40 DI Water 341.67 Post Addition: Acetic
Acid 8.50 Ammonium Sulfate 60.00
______________________________________
Using 3.0% seed, the dispersant system of the invention and 17.2%
salt, the process viscosity was maintained below 1,100 cp.
Example 3
In Example 3, process viscosities were measured during a process to
produce a dispersion polymer having a monomer mole ratio of
65/25/10 of the monomers AcAm, DMAEA.cndot.BCQ and DMAEA.cndot.MCQ,
respectively. The preparation contained 20% active monomer, 16%
salt and 6.67% of the preformed polymer of same composition as
recycled seed. The preparation also contained polyDMAEA.cndot.MCQ
and DADMAC-DMAEA.cndot.BCQ copolymer as dispersant polymers. The
ratio of the dispersant polymers was varied to minimize process
viscosities. Over a period of eight subsequent generations, peak
viscosity was no higher than 9,500 cp and was substantially lower
for all but one polymerization process. This demonstrates that the
invention maintains peak viscosity below about 10,000 cp and
generally maintains it below about 5,000 cp.
Example 4
Example 4 was the same as Example 3 with the following exceptions:
20% monomers, 17% salt and 5.0% recycled seed. Over a period of
eight subsequent generations, peak viscosity was no higher than
4,500 cp. This demonstrates that the invention maintains peak
viscosity below about 5,000 cp.
Example 5
Example 5 was the same as Example 3 with the following exceptions:
25% active monomers, 17% salt and 5.0% recycled seed. Over a period
of eight subsequent generations, peak viscosity was no higher than
5,000 cp. This demonstrates that the invention maintains peak
viscosity below about 5,000 cp.
Changes can be made in the composition, operation and arrangement
of the method of the present invention described herein without
departing from the concept and scope of the invention as defined in
the following claims:
* * * * *